There are known plasma emitters of charged particles based on a glow discharge at low gas pressures, where strong magnetic fields of the order of 10.sup.-2 -10.sup.-1 Tesla (T) are produced to decrease the operating pressure and increase the plasma density. Those plasma emitters are used to produce narrow, highly focused beams in the systems based on the reflection discharge, and ring beams in the systems, based on the magnetron discharge. However, applying a strong magnetic field creates a significant spatial non-uniformity in the generated plasma, which makes difficult the generation of beams with large cross-sectional area in such systems.
The generation of the uniform plasma in a large volume at low pressure is provided by the discharge with hollow cathode without applying a magnetic field. To sustain a stable discharge it is necessary that the length of the energy relaxation of the fast electrons, oscillating inside the hollow cathode would be comparable with their mean path before escaping from the cavity, which is provided by increasing the size of the system and decreasing the area of electron loss. The electron loss area equals the sum of the emission aperture area and the elements inside the system, which have positive potential with reference to the cathode.
The known ion emitters of this type consist of the hollow cathode with a multi-apertured emission window and a rod-shaped anode mounted inside the cathode. However, the ignition of such a discharge at low gas pressure is quite difficult because the ignition voltage of such a discharge is significantly higher than its operating voltage. That leads to the necessity for a special ignition system to provide for the increased voltage between the electrodes, or the creation of an initial plasma injected into the system to start the main discharge. That makes the design of the system and its power supply more complicated, and reduces the reliability of the whole device. Further, the operating parameters of the beams generated in such systems are limited, since, for the small sized internal volume under the conditions for the self-sustaining discharge, it is necessary to increase the consumption of gas, which reduces the electric strength of the accelerating gap, and, consequently, the operating voltage of the ion source; an increase in the size of the system at low pressures leads to the decrease of the plasma density and a corresponding decrease of the value and density of the emission current.